PURIFICATION AND ADDITION
Metal scrapyards need to ensure that they’re producing and selling materials of consistent quality to stay in business. In the latter stages of processing, metal is purified to remove any contaminants. One frequently used method of purification is called electrolysis. During electrolysis, an electric current is passed through the metal. This separates any impurities, depositing only the pure metal.
Sometimes a metal’s impurities are removed as it’s melted. Melting causes some of the impurities to rise to the top for easy separation. Electrolysis is necessary when returning the metal to near-new condition, and chemicals are often added to molten metals to increase their density.